Keeping an eye on the sky-1

With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary—the utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.
-Edwin Hubble

Few months ago Hubble completed its 20 years of space service. Through this blog post let me take you through some of my all time favorite snaps ( well, its actually difficult to say which one is not a favorite ), from the whole array of pictures that Hubble has taken. One must visit the Hubble site to get the complete story as to what Hubble has been doing.
Just in brief; this huge piece of mirrors, cameras, antennas and other stuff was put into orbit around Earth on 22nd April 1990. Since then it has been working tirelessly and increase our understanding of the universe. From new planets to dark energy Hubble has seen it all.
You can also read in details of Hubble’s history in Wikipedia


Into nothing:
This is what Hubble's WFPC2(Wide-Field Planetary Camera 2) camera came up with when it was made to stare at blank space(seemingly) for days:


From being just a blank sky to buzzing cluster of galaxies! Hubble made us realize how packed the space is!

Blast from the past:
This one is the image of a supernova(SN 1987a) that happened in 1987, one of the brightest in the last 400 years. Hubble has been monitoring the aftermaths.


Into the orion:
One of my favorites, the orion nebula. As in any Nebula action always happens here.New stars are formed , they spew out gases , hurricanes of stellar winds. From 1,500 light years away , here is what Hubble has for us:
Bit of explanation on what you are seeing:
Bowl is the radiation rich bright center made of the stellar winds and the star factory.
M43, the young star carving out its own space in the nebula.
Brown dwarfs are the failed stars which failed to kick start their nuclear fusion.
Arcs and bubbles are formed of charged particles from the stellar wind.

A peek into our future:
Billions of years hence our Sun is going blow its outer region and become a white dwarf. Hubble has brought us the image as to what may be our sun’s fate too. When stars around the size of our sun exhaust the hydrogen supply in their core, they start shrinking due to their gravity. But fusion still happens in the outer layers.The shrinking core heats up and causes the outer layers to expand. Finally outer layers burst and end up forming planetary nebula . A planetary nebula will exist till all the gases are dissipated into the space leaving behind the cool white dwarf. The best of the planetary nebula is the cat’s eye nebula.


The bright inner spot is the core of the star. The rings are the gases thrown out by the dying star.

There are still more to come , but in the subsequent posts.

In the Comfort Zone

The third planet from the sun, our Home; what made it so special? So ideal for the plethora of simple and complex organisms including us who can contemplate on “what makes Earth special”?


We have an atmosphere with right density, right pressure; the right temperature, and an ideal fluid to support life. But, is that all that makes Earth the right place for life to emerge? There is just one more essential parameter (which has made the other parameters possible). The distance from sun! A little nearer it would have been too hot, a little further too cold. Doesn’t that imply that for any given star if planets or moons happen to fall in this right place , then life might evolve on them? This region is called the Habitable zone or Goldilocks zone (after the same Goldilocks from “Goldilocks and three bears” who would have been part of your bedtime story as a kid) . But its not just the correct spot from a star that’s is essential for supporting life, but also the right location in the galaxy (galactic habitable zone). Near enough to the galactic center to have enough metals (to make it a rocky planet like ours) and far enough to remain protected from the high frequency radiations that is lethal to life forms similar to us (carbon based).

What makes such places hospitable? Simple! The perfect (or near perfect) temperature which can support liquid water, the one fluid that has changed or rather written the history of our planet. So when looking for earth-like life forms, it is such zones in the universe that should be the starting point for the search.
The above statement may be an oversimplification. For even on our own planet we have come across creatures called the extremophiles, living in deep hot sulphur filled vents, underneath ice sheaths in Antartica, in the darkest regions of ocean where no light penetrates; where one would have never imagined a possibility of existence of life. But even in these organisms survival has been possible because of liquid water( they have developed ways to keep water in liquid state within them).
Scientists studying the possibility of extraterrestrial life are trying to find and explore these comfort zones, where conditions seem to be like that on earth. Recently existence of a rocky planet in such a habitable zone has been observed for one of the close star (just 20 light years away) called Gliese 581.


The fourth planet from the star lies in the outskirts of this region. Intially the planet Gliese 581 d was thought to be too cold for supporting life, but around April 2009 it was confirmed that it lies on the border of habitability. All it needs to do now is make some green house gases, raise its temperature to become suitable for supporting life.

So as Goldilocks famous line goes (and reason why the name was given):
"This porridge is too hot," Goldilocks exclaimed.
So she tasted the porridge from the second bowl.
"This porridge is too cold."
So she tasted the last bowl of porridge.
"Ahhh, this porridge is just right!" she said happily.
And she ate it all up.
It has to be ‘just right’ nothing less, nothing more.